SeekerBlog

Charles sent me the link to The Earth Institute’s press release on an “air extraction” prototype by Global Research Technologies, LLC (GRT). The graphic at left depicts the “synthetic tree” structures.

There is very little more info at the company’s website. However, here is a modest interview with Prof. Klaus Lackner at Columbia University — a principal in the Earth Institute quoted prototype — which describes the process flow, envisioning 250,000 “synthetic trees” to capture the current annual global carbon output:

• capture CO2 from airstream via liquid sodium hydroxide

• remove carbon from liquid sodium hydroxide via solid calcium hydroxide

• release the concentrated CO2 from the calcium hydroxide by heating to 900 C

• sequester the CO2

There’s some general background information on air capture by University of Colorado policy researcher Roger Pielke, Jr. in The Simplest Solution to Eliminating U.S. Greenhouse Gas Emissions, where Roger proposes a policy thought experiment to examine the pros/cons of direct air capture at hypothetical costs ranging from $100 to $500/ton carbon. Included are links and some discussion of Lackner’s work. Excerpt from Roger’s post [see also comments]:

“Air capture” refers to the direct removal of carbon dioxide from the atmosphere. Leading work on this technology has been done by David Keith at the University of Calgary, his recent Ph.D. student Joshua Stolaroff, and separately by Klaus Lackner at Columbia University. Motivated by recent discussions on this site about the Massachusetts vs. EPA lawsuit, I wondered what the costs would be of neutralizing the carbon dioxide emissions of U.S. autos via air capture, and indeed all of U.S. emissions. Here is what I have come up with.

Air capture is a compelling technology because it requires no government regulation, no change in behavior, no international negotiations, and, most importantly from the standpoint of political action, no changes in energy production or use. Politically, it is therefore as simple and straightforward an approach as can be imagined. It is a top down technology in the sense that it can be used to “tune” the atmosphere to a desired concentration level. The downside is that it is expensive, but still far cheaper than the damages projected, for instance, in the recent Stern Review. Its ease in implementation and political simplicity more than offset its higher costs than other approaches to reducing carbon emissions.

In his recent dissertation (of which I have a copy but I am unaware if it is available online), Dr. Stolaroff suggests (his lower realistic estimate) that air capture technologies can remove carbon dioxide at a cost of $140/ton of carbon dioxide (or about $500/ton of carbon). In an interview with PBS earlier this year, Prof. Lackner suggested that the costs of direct air capture might eventually be as low as $30/ton of carbon dioxide (or about $100/ton of carbon). In the thought experiment below I’ll use both $100/ton and $500/ton.

…This solution is so simple and straightforward, I wonder why those concerned with global warming aren’t trumpeting it as a solution in the United States? Instead, the focus is on complicated and politically intractable approaches with dubious chances for success. Air capture is easy (compared to other solutions that have been proposed) to implement and politically requires only enough motivation to win a $1.00/gallon gas tax. If global warming is indeed going to cost us 5-20% of global GDP, how can we not pursue air capture?

What have I missed?

Note 1: that the Earth Institute director is economist Jeffrey Sachs. You may find Sachs’ talk at the Yale conference on the Stern Review of interest — Sachs was more optimistic about the impact of technology and consequently projected lower costs for mitigation efforts than other panelists. I’ve created 18 podcasts from the REAL streaming video of the Yale conference — you can find the two-part Sachs talk there — very worthwhile, as is the entire conference.

Note 2: that in his public lectures Ray Kurzweil often mentions his conviction/prediction that direct air carbon capture, based upon unspecified nanotech, will be successful before 2050 [??]. I’ll leave the validity of that forecast as a research topic for you dear reader…